I'd like to preface by saying that I am not an expert in Mughal history, although I have read quite a bit on the subject.

Most of my sources are from Abraham Eraly's "The Mughal Throne." I am personally not a huge fan of Eraly's historiography (he tends to be somewhat biased at times), however, I am unable to read original Mughal sources like the Akbarnama and the Baburnama, and don't have ready access to translations.

The Mughals and their Afghan predecessors had a propensity for lavishness from the very beginning of the dynasty. Babur's Uzbek uncles and cousins indulged excessively in (as described by Babur in the Baburnama) "vice and debauchery," consuming considerable wine and opium. Wine and opium were the choice drugs of aristocratic Mughal society, and Babur himself took to consuming considerable amounts of wine and some degree of opium (it is possible he took other drugs as well, however, I have only explicitly heard of these two). Babur continued his wine-drinking habits for the majority of his life, briefly abstaining in his middle age, but quickly returning to alcohol's seductions in his old age. Babur's son Humayun also indulged in narcotics, with Mirza Haidar describing among his many vices "the excessive use of opium." Note the word "excessive," the use of opium and alcohol was, in the minds of most Mughals, a necessary luxury of royalty. Babur believed that small doses of wine and opium stimulated his creativity and strengthened his mind towards politics, and the opinions of most Mughals were not much different. Similar traditions already existed in Islamic and Hindu India prior to the arrival of the Mughals, the sultans of Delhi often drank and distributed wine and the Rajputs of the kingdoms of Rajasthan believed opium sharpened their skills in battle.

From the luxuries of Babur and Humayun, we reach the reigns Akbar and Jahangir, mentioned in your question. While Akbar also drank wine, his indulgence in the more potent aspects of Mughal luxury was considerably more reserved than his father and grandfather. Akbar's sons however were a different story. The two sons that you mention were Murad and Daniyal, both of whom died of their alcoholism. Akbar tried to wean Daniyal off of wine following Murad's death, however, this proved ineffective, and Daniyal died after 40 days of withdrawal, according to Muhibb Ali (a court calligrapher), "longing for wine." Jahangir was, for all practical matters, no different from his troubled brothers, however, he was not exactly a "functioning" alcoholic. Jahangir had been, by his own admission, a drunkard since the age of 14, when he had first started drinking wine while in Punjab. Jahangir's alcoholism only worsened from there, and he drank as many as "20 cups" of distilled spirits as a young adult (spirits, unlike wine, had a considerable negative connotation to them in Mughal society. Liquor was not considered a royal luxury as wine was). Jahangir attempted to quit drinking after a while, however, he did not so much as quit drinking as he did turn to other drugs, such as opium and marijuana (unrelated, but Indian rulers traditionally ate marijuana rather than smoke it as we do today). Jahangir's drug habits often impeded his daily work, preventing him from attending meetings with his vassals, by the account of Sir Thomas Roe (British diplomat to the Mughal Empire), Jahangir was unable to "feed himself" by the end of many days, and instead had his food "thrust" into his mouth by servants. Such stupers also led to great mood swings, and Jahangir was apt to either severely punish his guests, or "without any reason...burst into tears." Indeed, there are far too many sources, ranging from both Mughal and European sources to suggest that the drunkenness of the Mughal emperors, especially Jahangir, was propaganda. As we have seen, Jahangir himself admitted that he had a problem, although he was not particularly keen on solving it.

Mughal drug use, especially alcohol use, did not stop with Jahangir, later Mughal aristocrats such as the court poet Mirza Ghalib also liberally drank wine and consumed opium. The Mughal opinion towards drugs can best be described by Jahangir's advice to Shah Jahan: "My boy, you are the father of children, and kings and princes drink wine."